<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
<style>
	#div1 {width: 200px; height: 150px; background: red; position: absolute; right: 0; bottom: 0}
</style>
<script>
	
window.onscroll = window.onresize= function(){
	var scrollTop = document.documentElement.scrollTop || document.body.scrollTop;
	var oDiv = document.getElementById('div1');
	alert(oDiv.offsetHeight );
	//alert(oDiv.Height); undefined
	oDiv.style.top = document.documentElement.clientHeight - oDiv.offsetHeight + scrollTop + 'px';
};	
</script>
</head>

<body style="height: 2000px">
<div id="div1">
	
</div>
</body>
</html>
